Cables
An example how to calculate voltage drop and size of electrical cable
According to the National Electrical Code, in order for general use circuits to operate reasonably efficiently, the maximum voltage drop for branch circuit conductors is 3% and for feeder and branch circuit conductors combined it is 5%. When designing circuits… Read more
Jun 30, 2014 | By Jignesh Parmar
Electric Motor
How to measure insulation resistance of a motor
If the motor is not put into operation immediately upon arrival, it is important to protect it against external factors like moisture, high temperature and impurities in order to avoid damage to the insulation. Before the motor is put into… Read more
Jun 09, 2014 | By Edvard Csanyi
Energy and Power
An Overview Of Grounding System (Grounded)
Continued from technical article: An Overview Of Grounding System (Ungrounded) Solidly grounded system Resistance grounded system Reason for resistance grounding System earthing at EHV level Let us assume that R phase (Phase-3 in figure-3) is shorted to ground than: If… Read more
Oct 14, 2013 | By Asif Eqbal
Energy and Power
Comparison Of Neutral Earthing Methods
Neutral earthing systems are very similar to circuit breakers in that they do nothing until something in the system goes wrong! There are several methods for system earthing which can be generally divided into three main categories: Insulated earthing, Solid… Read more
Sep 16, 2013 | By Edvard Csanyi
Energy and Power
Determining the soil resistivity to design a good substation grounding system
It is essential to determine the soil resistivity and maximum grid currents to design a substation grounding system. The touch and step voltages are directly proportional to these values. Overly conservative values of soil resistivity and grid current will increase… Read more
Sep 04, 2013 | By Edvard Csanyi
Energy and Power
How to Determine Correct Number of Earthing Electrodes (Strips, Plates and Pipes) – part 2
Continued from first part: How to Determine Correct Number of Earthing Electrodes (Strips, Plates and Pipes) – part 1 The Earth Resistance of Single Plate electrode is calculated as per IS 3040: R=ρ/A√(3.14/A) Where: ρ = Resistivity of Soil (Ω… Read more
May 13, 2013 | By Jignesh Parmar
Electrical Lectures
How to Determine Correct Number of Earthing Electrodes (Strips, Plates and Pipes) – part 1
Earthing Resistance and the number of earthing electrodes are both dependent on the resistivity of the soil as well as the amount of time it takes for fault current to pass through (one second or three seconds). The number of… Read more
Apr 05, 2013 | By Jignesh Parmar
Electrical Lectures
The Rheostat In Few Simple Words
A variable resistor can be made from a wirewound element, rather than a solid strip of material. This is called a rheostat. A rheostat can have either a rotary control or a sliding control. This depends on whether the nichrome… Read more
Mar 20, 2013 | By Edvard Csanyi
Energy and Power
An Overview Of Short Circuit Current (part 3)
Fault calculations are carried out to find the magnitude of fault current at various voltage levels of electrical system. One of the key components in the calculation process is to determine the total impedance of the circuit from the utility /… Read more
Mar 08, 2013 | By Asif Eqbal
Energy and Power
Inspection and Test Procedures for Metal-Enclosed Busways
Visual and Mechanical Inspection Electrical Tests Test Values Test Values – Visual and Mechanical Test Values – Electrical Tables: TABLE 100.12 – US Standard Fasteners Bolt-Torque Values for Electrical Connections TABLE 100.1 – Insulation Resistance Test Values Electrical Apparatus and… Read more
Dec 22, 2012 | By Edvard Csanyi
Energy and Power
Testing and Commissioning of Metal-Clad Switchgear
Electrical testing and commissioning of Metal-Clad switchgear is essential to the safe start for the first time, regardless of its size, type or industry. This article covers testing and start-up / commisioning procedures for all the components of medium voltage… Read more
Sep 24, 2012 | By Edvard Csanyi
Electrical Lectures
Water-and-Pipe Analogy for Ohm’s Law
Ohm’s Law also makes intuitive sense if you apply it to the water-and-pipe analogy. If we have a water pump that exerts pressure (voltage) to push water around a ”circuit” (current) through a restriction (resistance), we can model how the three… Read more
Aug 15, 2012 | By Edvard Csanyi
Cables
Locating underground electrical cable faults
Before attempting to locate underground cable faults on direct buried primary cable, it is necessary to know where the cable is located and what route it takes. If the fault is on secondary cable, knowing the exact route is even… Read more
Jul 13, 2012 | By Edvard Csanyi
Cables
Sizing of power cables for circuit breaker controlled feeders (part 3)
Continued from article Sizing of power cables for circuit breaker controlled feeders (part 2) This criterion is applied so that the cross sectional area of the cable is sufficient to keep the voltage drop (due to impedance of cable conductor)… Read more
May 17, 2012 | By Asif Eqbal
Electric Motor
Measurement of insulation resistance (IR) – Part 2
This article goes into details of insulation resistance values measured by Megger tester on many different kinds of equipment, such as switchgear, electrical wires & cables, electric motors, transmission & distribution lines, and other power system equipment. An insulation tester… Read more
Apr 29, 2012 | By Jignesh Parmar
